Field Biogeochemical Measurements in Support of Remote Sensing Signatures and Characterization of Permafrost Terrain: Integrated Technologies for Delineating Permafrost and Ground-State Conditions

This report highlights the acquisition of plant canopy spectral reflectance, leaf-level gas and fluorescence, and associated soil conditions at discrete locations along two transects located within the U.S. Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory (ERDC-CRREL), near Fairbanks, AK. Ecotones in interior Alaska have unique vegetative cover and heterogeneous terrains that are underlain by sporadic discontinuous permafrost. Permafrost thaw is expected to cause ecological consequences; and because vegetation and local soil microflora are tightly coupled, changes to this system offer a source of significant impacts on surface hydrology and soil strength. The objective of this study was to investigate potential relationships between vegetative vigor and soil biochemistry in permafrost-affected areas for use in the development of standoff sensors for mapping the subsurface composition of permafrost terrains and to help in predicting how and where thawing permafrost will alter vegetation and soil ecology. Our results showed that redox chemistry is an important driver of ecosystem dynamics, and we identified relationships between fluorescence and reducing conditions at these transects. While it is well known that redoxymorphic conditions help drive plant composition in wetlands, it is less apparent how permafrost thaw influences this dynamic. The original document contains color images.